One known way of manufacturing a light-weight mirror is to fix plates on a honeycomb core and to put a reflecting deposit on one of the plates (IBM Technical Disclosure Bulletin, Vol. 20, No. 12, May 1978, page 5121; U.S. Pat. No. 3,912,380).
It is also known that plastic materials and fibers may be used to make low mass mirrors or other optical components (Laser Focus, April 1985, pages 40 to 42; U.S. Pat. No. 4,463,055; French patent 2 215 631).
More precisely, French patent 2 215 631 describes a method of manufacturing a low mass optical component in which a stack is made of plies constituted by fibers impregnated with a polymerizable resin, with such a stack being applied and glued to at least one of two opposite faces of a core of cellular structure, with the resin being polymerized by heating and by applying pressure, and with a reflecting surface being formed on the stack.
A fundamental difficulty in the manufacture of a light-weight mirror lies in the fact that light weight is often obtained to the detriment of the mechanical properties of the mirror, and in particular of its stiffness.
It is thus very difficult to obtain a mirror which is simultaneously both light in weight and which has good mechanical properties.
The present invention seeks to provide an ultralight-weight mirror having improved mechanical qualities, in particular improved stiffness.